The invention pertains to a platform for a trailer composed of boards which are extruded from aluminum with the top and bottom panel portions joined by angularly disposed webs. The boards are transversely disposed, abutted against each other and welded at the edges to provide top and bottom panels which are parallel at the central portion and with the bottom panel sloping upwardly from the central portion toward the outer edges. The edge of the central portion has vertically disposed webs which extend therebelow and which are joined to inverted T-shaped elements to form supporting frame members which are in unit relation to the platform support thereabove.